The present invention relates in general to an information storage device having an information storage medium disposed in a removable cartridge and, more particularly, to a method and apparatus for storing calibration parameters used by the cartridge on the storage medium within the cartridge.
Over the past twenty years, computer technology has evolved very rapidly. One aspect of this evolution has been a progressively growing demand for increased storage capacity in memory devices, especially where the information storage medium is disposed in some form of removable cartridge. In this regard, just a little over a decade ago, the typical personal computer had a floppy disk drive which accepted floppy disk cartridges that contained 5.251xe2x80x3 disks having a storage capacity up to about 720 KB per cartridge. Not long thereafter, these devices gave way to a new generation of floppy disk drives which accepted smaller floppy disk cartridges that contained 3.5xe2x80x3 disks having higher storage capacities, up to about 1.44 MB per cartridge.
Subsequently, as the evolution continued, a further significant increase in storage capacity was realized in the industry by the introduction of a storage system having removable cartridges containing floppy-type disks with storage capacities on the order of 100 MB to 250 MB. Systems of this are commercially available under the tradename ZIP from Iomega Corporation of Roy, Utah, which is the Assignee of the present application. Thereafter, another significant increase in storage capacity was realized by the introduction of a system having removable cartridges with storage capacities on the order of 1 GB to 2 GB. Systems of this type are also available from Iomega Corporation, under the tradename JAZ. The cartridges used in this system had a hard disk in an unsealed housing, with the read/write head in the drive. These two products have each enjoyed immense commercial success. Nevertheless, the demand for still greater storage capacities in removable cartridges continues to progressively increase, such there is a current need for cartridges capable of storing 5 GB to 20 GB, or even more.
The types of removable cartridges discussed above each contain a rotatably supported storage medium within an unsealed housing. The read/write heads, with associated circuitry and support structure, are in the drive rather than in the cartridge. Significantly higher storage capacities exist in hard disk technology of the type used in non-removable hard disk drives, where the disk and head are both within a sealed housing. However, there are problems involved in attempting to carry use of this technology over to removable cartridges. This is due in part to the fact that a high-capacity hard disk is highly sensitive to environmental factors such as dust and static electricity. Consequently, in order to achieve high storage densities, the sealed housing is needed for the hard disk itself, as well as for some associated components, such as the read/write heads, which must be within the sealed housing and thus within the cartridge. Although some prior attempts have been made to use hard disk technology within a sealed housing in a removable cartridge, these attempts never resulted in a product which has had any significant level of commercial success. Instead, the types of cartridges discussed above continue to dominate the market.
Where a sealed housing has been used, the most typical prior approach was to incorporate the entire structure of a hard disk drive unit into the cartridge, such that the cartridge was not significantly different from a self-contained, standalone hard disk drive unit. In a sense, this was not a true cartridge at all, but simply a complete and self-contained hard disk drive which could be removed more easily than most from the system in which it was installed. One example of such a device is a system which was commercially available as the model P3250AR removable hard disk drive from Kalok Corporation of Sunnyvale, Calif. Another example of such a system is disclosed in Blackborow et al. U.S. Pat. No. 5,041,924. Since each cartridge in this type of system is effectively a standalone, self-contained disk drive, each cartridge is relatively heavy and expensive.
A different prior approach was to split the components of a self-contained hard disk drive into two groups, and to include one group within a sealed housing in each removable cartridge, and the other group in a drive which can removably receive one of the cartridges. Examples of this approach appear in Stollorz U.S. Pat. No. 4,359,762, Iftikar et al. U.S. Pat. No. 4,965,691, Chan U.S. Pat. No. 5,214,550, Kamo et al. U.S. Pat. No. 5,235,481, Witt et al. U.S. Pat. No. 5,317,464, and Lockhart et al. U.S. Pat. No. 5,412,522. While pre-existing products using this approach were adequate for their intended purposes, they were not satisfactory in all respects, and none of them experienced any significant commercial success.
In this regard, one consideration is that, where circuitry in a drive effects alignment of a read/write head with a disk using feedback servo control, the drive must be aware of certain servo parameters which define appropriate control characteristics suitable for use with that particular type of hard disk. Where a given drive is to be used with various different types of cartridges, the appropriate servo parameters may vary from one cartridge type to another. Moreover, even for a particular type of cartridge, appropriate servo parameters may vary somewhat from cartridge to cartridge, especially where optimum accuracy is desirable. Consequently, one existing approach is to have the drive carry out a calibration procedure each time a cartridge is inserted. However, the time required to carry out such a calibration procedure can be sufficiently long that it is perceptible to a human operator. Further, as storage densities increase, and in situations where a drive is to be used with different types of cartridges, the number and/or complexity of the calibrations carried out in the calibration procedure increase, thereby increasing the initial start up time. A further factor that can come into play involves environmental conditions such as temperature, because the calibration parameters that may be optimum for one temperature range may not be the calibration parameters that are optimum for a different temperature range.
Yet another consideration is the fact that, if an error is detected, a procedure commonly known as a retry method is typically carried out in an attempt to recover the data which was subject to the error. A number of different retry methods are known in the art, and it is common to successively try various different retry methods until one of them is successful. However, each of these retry methods takes a finite amount of time. Where a number of different retry methods are tried in succession before a successful method is found, there can be a delay which is perceptible to and which can annoy a human operator.
Still another consideration is that, when a problem is encountered with a cartridge, the cartridge may be returned to the manufacturer. In order to efficiently determine the problem, so as to facilitate repair of the cartridge or permit alteration of the cartridge design in order to avoid similar future problems, it would be helpful to the manufacturer to have some historical information about the use of the cartridge. As one example, it would be helpful to the manufacturer to know whether the cartridge failed early in its expected operational lifetime, or toward the end of its operational lifetime following numerous insertions into a number of different drives.
From the foregoing, it will be appreciated that a need has arisen for a method and apparatus for operating an information storage cartridge which includes a port and an information storage medium having an information storage surface, so as to efficiently determine suitable calibration parameters for use of the cartridge with each of various different receiving units, including storage of the calibration parameters on the storage medium.
According to one form of the present invention, a method and apparatus are provided to address this need, and involve: storing on the storage surface information which includes control information, the control information including a plurality of control parameter sets which each correspond to a respective receiving unit into which the cartridge can be removably inserted; supporting the storage medium and a head for relative movement in a manner causing the head to move relative to the surface while remaining adjacent thereto; transferring information between the port and the storage medium, including use of the head to effect at least one of reading information from and writing information to the storage medium; reading the control information from the information storage surface using the head; selecting from the control information one of the control parameter sets which corresponds to a respective receiving unit into which the cartridge is currently inserted; and thereafter effecting the relative movement of the head and the storage medium as a function of the selected control parameter set.